Tate trying to save Violet's life during episode 6. At the end of the episode, he tells her that he loves her and that he will leave her alone, if that's what she wants. It's not. The episode ends with her holding him, like he'd held her earlier.
Takes on a whole new light with the reveal that he failed to save her.
In the season finale, all the Harmons reuniting as ghosts. Especially when they're putting up a Christmas tree. Bonus points that it seems Moira is now a part of the family.
On that note, Vivien asking Moira to be her newborn's godmother.